Pour spout cartons made entirely of paperboard are well known in the art. For example, U.S. Pat. 5,531,376, which is incorporated herein by reference, discloses a carton having a paperboard pour spout. The pour spout comprises a front panel that is formed from a section of a vertical side wall of the carton and that is hingedly connected thereto along a horizontal fold line for pivotal movement between a closed position and an open position. The front panel has a pair of vertical opposed side edges and an upper edge bridging the side edges. The perimeter of the front panel on the interior surface of the side wall defines a pour spout opening having two opposed vertical edges. There is a cutout above the front panel to enable one to grasp the upper edge of the front panel to open the pour spout. A back panel is adhered to the interior surface of the front panel. A pair of wings are hingedly connected to the back panel along opposed vertical parallel fold lines. A backboard is adhered to the interior surface of the side wall such that the backboard occludes the cutout to prevent undesired egress of the contents from the carton or ingress of foreign matter into the carton. The carton is made from a unitary blank, but it requires complicated folding and gluing to form the pour spout assembly, uses more paperboard than necessary, and has several layers of paperboard that interfere with stacking and machinability of the carton in form, fill and seal packaging machines. The pour spout carton of this invention is easy to manufacture from a minimal amount of paperboard, yet provides excellent performance in being siftproof, easy to open and reclose, and easy to stack and machine in form, fill and seal packaging machines.